Small (<2.0-cm) Breast Cancers: Mammographic and US Findings at US-guided Cryoablation—Initial Experience

Cryotherapy in the Treatment of Early-Stage Breast Cancer

Breast cancer is one of the most common malignancies, affecting millions of people worldwide annually. The treatment paradigm for early-stage breast cancer is in flux. The focus is now on opportunities to de-escalation treatment to minimize morbidity and maximize patients' quality of life. Recently, percutaneous minimally invasive ablative techniques have been explored. Early trials in small population of patients demonstrated cryoablation to be effective, safe, and well-tolerated in an outpatient setting. Subsequent surgical resection was performed and the ablation success rate was the highest if the tumor was less than 1.5 cm and with < 25% ductal carcinoma in situ component. ACOSOG Alliance Z1072, a phase II trial with curative intent, demonstrated 100% ablation in all tumors smaller than 1 cm and 92% success in lesions without multifocal disease and less than 2 cm in size. There are ongoing prospective clinical trials to investigate the efficacy of cryoablation without surgical excision for treatment of early-stage breast cancer. FROST (Freezing Instead of Removal Of Small Tumors) started in 2016 is ongoing, ICE3 (Cryoablation of Low Risk Small Breast Cancer) started in 2014 just released 5 years results, and COOL-IT: Cryoablation vs Lumpectomy in T1 Breast Cancers is also ongoing. These prospective trials will expand our knowledge on the safety and value of cryoablation. It is crucial to understand the indications, technical nuances, and distinctive imaging findings for cryoablation as it has potential to revolutionize standard surgical practice.

Explainable breast cancer molecular expression prediction using multi-task deep-learning based on 3D whole breast ultrasound

OBJECTIVES

To noninvasively estimate three breast cancer biomarkers, estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) and enhance performance and interpretability via multi-task deep learning.

METHODS

The study included 388 breast cancer patients who received the 3D whole breast ultrasound system (3DWBUS) examinations at Xijing Hospital between October 2020 and September 2021. Two predictive models, a single-task and a multi-task, were developed; the former predicts biomarker expression, while the latter combines tumor segmentation with biomarker prediction to enhance interpretability. Performance evaluation included individual and overall prediction metrics, and Delong's test was used for performance comparison. The models' attention regions were visualized using Grad-CAM + + technology.

RESULTS

All patients were randomly split into a training set (n = 240, 62%), a validation set (n = 60, 15%), and a test set (n = 88, 23%). In the individual evaluation of ER, PR, and HER2 expression prediction, the single-task and multi-task models achieved respective AUCs of 0.809 and 0.735 for ER, 0.688 and 0.767 for PR, and 0.626 and 0.697 for HER2, as observed in the test set. In the overall evaluation, the multi-task model demonstrated superior performance in the test set, achieving a higher macro AUC of 0.733, in contrast to 0.708 for the single-task model. The Grad-CAM + + method revealed that the multi-task model exhibited a stronger focus on diseased tissue areas, improving the interpretability of how the model worked.

CONCLUSION

Both models demonstrated impressive performance, with the multi-task model excelling in accuracy and offering improved interpretability on noninvasive 3DWBUS images using Grad-CAM + + technology.

CRITICAL RELEVANCE STATEMENT

The multi-task deep learning model exhibits effective prediction for breast cancer biomarkers, offering direct biomarker identification and improved clinical interpretability, potentially boosting the efficiency of targeted drug screening.

KEY POINTS

Tumoral biomarkers are paramount for determining breast cancer treatment. The multi-task model can improve prediction performance, and improve interpretability in clinical practice. The 3D whole breast ultrasound system-based deep learning models excelled in predicting breast cancer biomarkers.

Defining Breast Cryoablation Treatment Success: A Guide for the Curative and Palliative Treatment of Breast Cancer

RATIONALE AND OBJECTIVES

Recent ICE3 trial of breast cryoablation for breast cancer demonstrated 98% success rate, similar to breast-conserving surgery. However, ICE3 and other published studies did not differentiate curative from palliative treatment nor define patient-specific treatment objectives. We sought to define treatment success of curative and palliative breast cryoablation for breast cancer in meeting procedure objectives and patient-specific treatment objectives.

MATERIALS AND METHODS

We conducted a retrospective analysis of breast cancer patients who underwent breast cryoablation during 2021-2024. Breast radiologists performed outpatient cryoablation using local anesthesia and argon gas cryoprobes under ultrasound or MRI guidance. Patient demographics, referral indications, tumor characteristics, procedure details, and imaging follow-up findings were analyzed. Cryoablation was categorized as curative or palliative. Treatment success was defined as achievement of both procedure and patient-specific treatment objectives.

RESULTS

Breast cryoablation was performed for 34 lesions in 29 patients with N0M0 (n = 25), N1M0 (n = 2), N2M0 (n = 1), and N0M1 (n = 1) disease. Most tumors were invasive ductal carcinoma (IDC), low to intermediate grade, estrogen receptor (ER) and progesterone receptor (PR) positive and HER2 negative (23 tumors, 68%). Tumor size ranged from 0.4-1.9 (median 0.8) cm for curative cryoablation and 0.6-6.0 (median 1.3) cm for palliative cryoablation. For 27 patients with follow-up imaging, ablation was curative in 14 patients, 14 tumors and palliative in 13 patients, 18 lesions. Imaging follow-up time ranged from 3 to 26 (median 16) months, > 12 months in 22 of 27 patients and 25 of 32 tumors. Complications were limited to 2 cases of skin frost injury, 1 mild and 1 moderate. Treatment success was achieved in 13 of 14 patients with curative and all 13 patients with palliative cryoablation.

CONCLUSION

Our study defines treatment success for curative and palliative breast cryoablation, demonstrates breast cryoablation achieves not only procedure (technical) but also patient-specific treatment objectives without significant complications, and may serve as guide for integrating breast cryoablation in the treatment of breast cancer patients.

Breast Cryoablation, From the AJR "How We Do It" Special Series

Breast cryoablation is a minimally invasive image-guided percutaneous procedure to treat fibroadenomas and early-stage breast cancer utilizing liquid nitrogen or argon gas to create extremely cold temperatures that devitalize targeted tissue. Although more long term data are needed, this outpatient procedure is well tolerated and carries minimal risks, including non-target thermal injury that can be mitigated by careful planning and proper technique. Building a sustainable breast cryoablation service in a radiology practice poses several practical considerations, such as training proceduralists, purchasing equipment, recruiting patients, and understanding the revenue cycle. This article describes aspects of the radiologist's role in this procedure, including implementation of a breast ablation program, patient selection, technical details related to intervention, and expected postprocedural outcomes.

Role of Interventional Radiology in Managing Primary and Metastatic Breast Cancer

Percutaneous image-guided locoregional therapies are emerging in the treatment of primary and metastatic breast cancer. Cryoablation has emerged as the dominant ablative approach as an alternative to surgery for primary breast cancer in patients who do not wish to have surgery or are poor surgical candidates. Cryoablation is well tolerated and provides excellent local control and cosmesis. Thermal ablation may also be used in the treatment of oligometastatic breast cancer, allowing patients to achieve long disease-free intervals. Transarterial therapies have been studied in the treatment of oligoprogressive hepatic metastasis, though further supportive data would be helpful to demonstrate its efficacy.

Treatment Options for Early Stage Inoperable Breast Cancer: Cryoablation or Radiotherapy?

Background

Surgical removal of the tumour is the gold standard treatment for early stage invasive breast cancer. However, with a global ageing population, a larger number of diagnoses are occurring in women with comorbidities that render them unsuitable for surgery. Hence, it is of interest to explore alternative treatment strategies for this group of women.

Summary

Our narrative review aims to explore two such techniques, cryoablation and external beam radiotherapy, providing a brief summary of the evidence behind each technique. Following this, we discuss which groups of patients would gain the most benefit from each technique. Factors favouring the use of radiotherapy include patients with larger tumours, more superficial tumours, and those with less well-demarcated tumours where there is uncertainty regarding tumour extent. Meanwhile, patients who may benefit more from cryoablation include those who desire a smaller number of treatment sessions, have concerns regarding cosmesis and skin pigmentation, or who have relative contraindications to radiotherapy such as scleroderma, systemic lupus erythematosus, reduced lung function, or cardiac comorbidities.

Key Messages

Continued advancements in both cryoablation and radiotherapy technologies are taking place, in tandem with imaging technologies enabling greater certainty in tumour detection and delineation. These factors will help increase local control rates in this group of non-operable early stage breast cancer patients. Through this review, we hope to aid in the clinical decision-making process regarding the selection and referral of patients for each treatment.

Cryoablation Therapy for Early-Stage Breast Cancer: Evidence and Rationale

Recent advances in breast cancer research and treatment propel a paradigm shift toward less aggressive and less invasive treatment for some early-stage breast cancer. Select patients with small, low-risk tumors may benefit from a less aggressive approach with de-escalated local therapy. Cryoablation of breast cancer is an emerging nonsurgical treatment alternative to breast-conserving surgery. Advantages of cryoablation over surgery include the use of local anesthesia, faster recovery, improved cosmesis, and cost savings. Proper patient selection and meticulous technique are keys to achieving successful clinical outcomes. The best candidates for cryoablation have unifocal invasive ductal carcinoma tumors that are low grade, hormone receptor positive, and ≤1.5 cm in size. In this review, we outline the current evidence, patient selection criteria, procedural technique, pre- and postablation imaging, and the advantages and limitations of cryoablation therapy.

Breast Cancer Cryoablation Fundamentals Past and Present: Technique Optimization and Imaging Pearls

Surgical treatment for breast cancer has evolved from radical mastectomy to modified radical mastectomy to breast-conserving surgery. As the de-escalation of surgical treatment for breast cancer continues, nonsurgical treatment for early-stage breast cancer with favorable ancillary features (low grade, positivity for hormone receptors) is being explored. Of the nonsurgical treatment options, cryoablation has demonstrated the greatest appeal, proven to be effective, safe, well tolerated, and feasible in an outpatient setting with local anesthetic alone. Results of past and interim results of current trials of cryoablation of stage I low-grade breast cancer with curative intent are promising, with an overall clinical success rate of 98% and recurrence rates consistent with those expected following lumpectomy. Cryoablation is also an alternative palliative treatment for patients who cannot tolerate or who have disease that is refractory to or recurs after standard-of-care breast cancer treatment and may have immunological therapeutic effects, warranting future research. Understanding the indications and optimal technique for breast cancer cryoablation and understanding typical imaging findings after cryoablation are essential to ensure the success of the procedure in carefully selected patients.

The Evolving Role of Cryosurgery in Breast Cancer Management: A Comprehensive Review

Breast cancer is the most commonly diagnosed type of cancer, accounting for approximately one in eight cancer diagnoses worldwide. In 2020, there were approximately 2.3 million new cases of breast cancer globally, resulting in around 685,000 deaths. Consequently, there is an ongoing need to develop innovative therapeutic approaches that can improve both clinical outcomes and patient quality of life. The use of ultra-low cryogenic temperatures, facilitated by cryogenic media such as liquid nitrogen, has revolutionized the biomedical field and opened up new possibilities for advanced clinical treatments, including cryosurgery. Cryosurgery has demonstrated its feasibility as a minimally invasive technique for destroying breast tumors and eliciting a significant antitumor immune response in the host. This feature sets cryosurgery apart from other ablative techniques. It has been shown to be well tolerated and effective, offering several advantages such as simplicity, the avoidance of general anesthesia, minimal pain, low morbidity, short recovery time, cost-effectiveness, and notably, improved aesthetic outcomes. The reviewed studies indicate that cryosurgery holds promise in the management of early-stage breast cancer and metastatic disease, especially in triple-negative and Her2-positive molecular subtypes in conjunction with checkpoint inhibitors and anti-Her2 antibodies, respectively. Furthermore, the effectiveness of cryosurgery in the management of ductal carcinoma in situ should be investigated as an alternative modality to surgery or surveillance. The minimally invasive nature of cryosurgery has the potential to significantly enhance the quality of life for patients.

Breast Cancer Cryoablation in the Multidisciplinary Setting: Practical Guidelines for Patients and Physicians

Breast cancer cryoablation has emerged as a minimally invasive alternative to lumpectomy for treating early-stage breast cancer. However, no consensus exists on what should be considered the standard of care for the multidisciplinary management of patients treated with breast cancer cryoablation. In lieu of national guidelines, this review of the literature provides a multidisciplinary framework and an evidence-based discussion of the integration of "standard of care practices" in the comprehensive management of breast cancer cryoablation patients.

The Role of Cryoablation in Breast Cancer Beyond the Oncologic Control: COST and Breast-Q Patient-Reported Outcomes

BACKGROUND

Cryoablation has been established as a minimally invasive alternative to resection of early-stage breast cancer; however, there are no data on the cost and impact on patients' financial, psychosocial, sexual, physical, and cosmetic outcomes utilizing this approach. This study compares cost-effectiveness and patient-reported quality-of-life factors in cryoablation versus resection.

METHODS

Women with early-stage, low-risk infiltrating ductal carcinomas ≤ 1.5 cm underwent cryoablation or resection. Adjuvant therapy was provided according to tumor board recommendations. Direct and indirect costs were tracked for both groups. Financial toxicity and well-being outcome were measured by administering the Comprehensive Score of Financial Toxicity (COST) and BREAST-Q surveys, respectively, at 6-month follow-up.

RESULTS

Of the 34 eligible patients, 14 (41.1%) consented for cryoablation and 20 (58.8%) underwent resection. The median (centile) (range) follow-up was 35.0 (21.3) (15-50) months for cryoablation vs. 25 (20.8) (17-50) months for resection [p = 0.6479]. Mean (standard deviation) cost of care for cryoablation versus resection was $2221.70 (615.70) versus $16,896.50 (1332.40) [p < 0.0001], and median financial well-being scores for the cryoablation versus resection groups were 38.0 (34.5, 40.0) versus 10 (5.3, 14.0) [p < 0.0001]. Poor financial well-being was directly correlated with the cost of care [p < 0.0001]. Median psychosocial well-being scores were similar across both groups, however the cryoablation group had higher scores for physical [100 (100, 100) vs. 89 (79, 100); p = 0.0141], sexual [100 (91, 100) vs. 91 (87.5, 91); p = 0.0079], and cosmetic [100 (100, 100) vs. 88 (88, 100); p = 0.0171] outcomes.

CONCLUSION

Cryoablation offers a cost-effective and quality-of-life advantage compared with resection for early-stage, low-risk breast cancer.

Percutaneous Management of Breast Cancer: a Systematic Review

PURPOSE OF REVIEW

Surgical treatment of breast cancer is becoming increasingly more minimally invasive. We review the development status of percutaneous management for primary breast cancer and the evidence relating to tumor size as a fundamental determinant of treatment clinical outcome.

RECENT FINDINGS

It is safe and feasible for percutaneous management to treat breast cancer. For tumor size ≤ 2 cm, percutaneous management is a promising alternative modality. For tumor size ≤ 3 cm, it is controversial whether percutaneous management can achieve similar effects to surgery, especially its long-term effects. For tumor size > 3 cm, it is still in the initial exploration stage and showed the potential in the treatment of unresectable cancer by benefitting the local control of primary cancer. Percutaneous management of breast cancer is a valuable method for breast cancer treatment in selected patients. However, it will be necessary to provide the high level of evidence for widespread clinical application.

Landscape of the Peripheral Immune Response Induced by Local Microwave Ablation in Patients with Breast Cancer

Minimally invasive thermal therapies have been attempted in the treatment of breast cancer, and the immune response induced by these therapies has not been fully reported. A clinical trial is performed to determine the effect of microwave ablation (MWA) in the treatment of early-stage breast cancer. The authors perform single-cell RNA sequencing on peripheral blood mononuclear cells (PBMCs) from six patients before and after ablation. NK and CD8⁺ T cells are activated by MWA of breast cancer, with the increased inhibitory signature of CD8⁺ T cells but not dysfunctional. Enhanced co-stimulatory signature of CD4⁺ T cells is observed and increased frequency of ICOS⁺ CD4⁺ T cells after MWA is confirmed by flow cytometric analysis. After ablation, T-cell clones expand with increased T-cell receptor diversities. Activated antigen receptor-mediated signaling pathways are found in B cells. Enhanced interactions between B cells and CD4⁺ T cells are found, indicating that B cells are important antigen-presenting cells that initiate CD4⁺ T cells in MWA-induced immune response. Blockade of CTLA-4 or PD-1 of post-MWA PBMCs show higher T-cell activity than that of pre-MWA PBMCs. This study provide global characteristics of MWA-induced systemic immune response and pave a way for the identification of potential targets to improve the immune response.

Optimal localization strategies for non-palpable breast cancers –A network meta-analysis of randomized controlled trials

Purpose

Mammographic screening programmes have increased detection rates of non-palpable breast cancers. In these cases, wire-guided localization (WGL) is the most common approach used to guide breast conserving surgery (BCS). Several RCTs have compared WGL to a range of novel localization techniques. We aimed to perform a network meta-analysis (NMA) of randomized controlled trials (RCTs) comparing methods of non-palpable breast cancer localization.

Methods

A NMA was performed according to PRISMA-NMA guidelines. Analysis was performed using R packages and Shiny.

Results

24 RCTs assessing 9 tumour localization methods in 4236 breasts were included. Margin positivity and reoperation rates were 16.9% (714/4236) and 14.3% (409/2870) respectively. Cryo-assisted localization had the highest margin positivity (28.2%, 58/206) and reoperation (18.9%, 39/206) rates. Compared to WGL (n = 2045 from 24 RCTs) only ultrasound guided localization (USGL) (n = 316 from 3 RCTs) significantly lowered margin positivity (odds ratio (OR): 0.192, 95% confidence interval (CI): 0.079–0.450) and reoperation rates (OR: 0.182, 95%CI: 0.069–0.434). Anchor-guided localization (n = 52, 1 RCT) significantly lowered margin positivity (OR: 0.229, 95%CI: 0.050–0.938) and magnetic-marker localization improved patient satisfaction (OR: 0.021, 95%CI: 0.001–0.548). There was no difference in operation duration, overall complications, haematoma, seroma, surgical site infection rates, or specimen size/vol/wt between methods.

Conclusion

USGL and AGL are non-inferior to WGL for the localization of non-palpable breast cancers. The reported data suggests that these techniques confer reduced margin positivity rates and requirement for re-operation. However, caution when interpreting results relating to RCTs with small sample sizes and further validation is required in larger prospective, randomized studies.

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Ultrasound-guided (USGL) and anchor-guided (AGL) localization had optimal outcomes.

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These methods significantly lowered margin positivity (odds ratio: 0.192 & 0.229).

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However, small sample sizes in trials evaluating USGL and AGL limit these results.

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Operation duration, complications, or specimen data were comparable for all methods.

Image-guided Microinvasive Percutaneous Treatment of Breast Lesions: Where Do We Stand?

Treatment of breast lesions has evolved toward the use of less-invasive or minimally invasive techniques. Minimally invasive treatments destroy focal groups of cells without surgery; hence, less anesthesia is required, better cosmetic outcomes are achieved because of minimal (if any) scarring, and recovery times are shorter. These techniques include cryoablation, radiofrequency ablation, microwave ablation, high-intensity focused US, laser therapy, vacuum-assisted excision, and irreversible electroporation. Each modality involves the use of different mechanisms and requires specific considerations for application. To date, only cryoablation and vacuum-assisted excision have received U.S. Food and Drug Administration approval for treatment of fibroadenomas and have been implemented as part of the treatment algorithm by the American Society of Breast Surgeons. Several clinical studies on this topic have been performed on outcomes in patients with breast cancer who were treated with these techniques. The results are promising, with more data for radiofrequency ablation and cryoablation available than for other minimally invasive methods for treatment of early-stage breast cancer. Clinical decisions should be made on a case-by-case basis, according to the availability of the technique. MRI is the most effective imaging modality for postprocedural follow-up, with the pattern of enhancement differentiating residual or recurrent disease from postprocedural changes. ^©RSNA, 2021.

Precision Breast-Conserving Surgery With Microwave Ablation Guidance: A Pilot Single-Center, Prospective Cohort Study

Introduction

Negative margins in breast-conserving surgery (BCS) are essential for preventing recurrence. The aim of this study was to determine the use of preoperative microwave ablation (MWA) in the guidance of BCS for early-stage breast cancer and access whether MWA could influence the rates of positive resection margins.

Methods

From 2016 to 2018, 22 women with T1/T2 invasive breast cancer were enrolled for MWA prospectively in the guidance of BCS. US-guided MWA was performed under local anesthesia, followed by BCS and sentinel lymph node biopsy (SLNB) one week after ablation. Women who underwent palpation-guided BCS directly were included as control, and propensity score matching analysis was applied.

Results

MWA was performed in 22 patients. Of the 21 MWA cases with effect information, the mean tumor size in US was 20.9 ± 6.2 mm (6-37 mm). Compared with control group (BCS directly), a lower rate of positive/close margins was observed in MWA guidance group (P = 0.018), and MWA caused a higher rate of accurate surgery (the largest margin ≤ 3 cm and the smallest margin ≥ 1mm, P = 0.042). Of these 21 patients treated with MWA, 18 were candidates for SLNB. And sentinel lymph nodes were successfully identified in all cases, and no recurrence was found with a mean follow-up of 23 months.

Conclusion

For patients with T1/T2 breast cancer, the application of preoperative MWA could guide BCS accurately without impairing SLNB. Clinical trials with long-term results are required to validate MWA in the guidance for breast cancer excision.

Microwave ablation of primary breast cancer inhibits metastatic progression in model mice via activation of natural killer cells

Surgery is essential for controlling the symptoms and complications of stage IV breast cancer. However, locoregional treatment of primary tumors often results in distant progression, including lung metastasis, the most common type of visceral metastasis. As a minimally invasive thermal therapy, microwave ablation (MWA) has been attempted in the treatment of breast cancer, but the innate immune response after MWA has not yet been reported. Using two murine models of stage IV breast cancer, we found that MWA of primary breast cancer inhibited the progression of lung metastasis and improved survival. NK cells were activated after MWA of the primary tumor and exhibited enhanced cytotoxic functions, and the cytotoxic pathways of NK cells were activated. Depletion experiments showed that NK cells but not CD4+ or CD8+ T cells played a pivotal role in prolonging survival. Then, we found that compared with surgery or control treatment, MWA of the primary tumor induced completely different NK-cell-related cytokine profiles. Macrophages were activated after MWA of the primary tumor and produced IL-15 that activated NK cells to inhibit the progression of metastasis. In addition, MWA of human breast cancer stimulated an autologous NK-cell response. These results demonstrate that MWA of the primary tumor in metastatic breast cancer inhibits metastatic progression via the macrophage/IL-15/NK-cell axis. MWA of the primary tumor may be a promising treatment strategy for de novo stage IV breast cancer, although further substantiation is essential for clinical testing.

Cryo-Assisted Resection En Bloc, and Cryoablation In Situ, of Primary Breast Cancer Coupled With Intraoperative Ultrasound-Guided Tracer Injection: A Preliminary Clinical Study

The aim of the study was to perform cryosurgery on a primary breast tumor, coupled with simultaneous peritumoral and intratumoral tracer injection of a blue dye, to evaluate lymphatic mapping. We explored the ability of our strategy to prevent tumor cells, but not that of injected tracers, to migrate to the lymphovascular drainage during conventional resection of frozen breast malignancies. Seventeen patients aged 51 (14) years (mean [standard deviation]), presenting primary breast cancer with stage I to IV, were randomly selected and treated in The Rudolfinerhaus Private Clinic in Vienna, Austria, and included in this preliminary clinical study. Under intraoperative ultrasound, 14 patients underwent curative cryo-assisted tumor resection en bloc, coupled with peritumoral tracer injection, which consisted of complete tumor freezing and concomitant peritumor injection with a blue dye, before resection and sentinel lymph node dissection (group A). Group B consists of 3 patients previously refused any standard therapy and had palliative tumor cryoablation in situ combined with intratumoral tracer injection. The intraoperative ultrasound facilitated needle positioning and dye injection timing. In group A, the frozen site extruded the dye that was distributed through the unfrozen tumor, the breast tissue, and the resection cavity for 12 patients. One to 4 lymph nodes were stained for 10 of 14 patients. The resection margin was evaluable. Our intraoperative ultrasound-guided performance revealed the injection and migration of a blue dye during the frozen resection en bloc and cryoablation in situ of primary breast tumors. Sentinel lymph node mapping, pathological determination of the tumor, and resection margins were achievable. The study paves the way for intraoperative cryo-assisted therapeutic strategies for breast cancer.

The Evolving Role of Ultrasound Guided Percutaneous Laser Ablation in Elderly Unresectable Breast Cancer Patients: A Feasibility Pilot Study

Background and Objectives

Breast-conserving surgery represents the standard of care for the treatment of small breast cancers. However, there is a population of patients who cannot undergo the standard surgical procedures due to several reasons such as age, performance status, or comorbidity. Our aim was to investigate the feasibility and safety of percutaneous US-guided laser ablation for unresectable unifocal breast cancer (BC).

Methods

Between December 2012 and March 2017, 12 consecutive patients underwent percutaneous US-guided laser ablation as radical treatment of primary inoperable unifocal BC.

Results

At median follow-up of 28.5 months (range 6-51), no residual disease or progression occurred; the overall success rate for complete tumor ablation was therefore 100%. No significant operative side effects were observed, with only 2 (13.3%) experiencing slight to mild pain during the procedure, and all patients complained of a mild dull aching pain in the first week after procedure.

Conclusions

Laser ablation promises to be a safe and feasible approach in those patients who are not eligible to the standard surgical approach. However, longer follow-up results and larger studies are strongly needed.

Eligibility of patients for minimally invasive breast cancer therapy based on MRI analysis of tumor proximity to skin and pectoral muscle

There is growing interest in minimally invasive breast cancer therapy. Eligibility of patients is, however, dependent on several factors related to the tumor and treatment technology. The aim of this study is to assess the proportion of patients eligible for minimally invasive breast cancer therapy for different safety and treatment margins based on breast tumor location. Patients with invasive ductal cancer were selected from the MARGINS cohort. Semiautomatic segmentation of tumor, skin, and pectoral muscle was performed in Magnetic Resonance images. Shortest distances of tumors to critical organs (ie, skin and pectoral muscle) were calculated. Proportions of eligible patients were determined for different safety and treatment margins. Three-hundred-forty-eight patients with 351 tumors were included. If a 10 mm safety margin to skin and pectoral muscle is required without treatment margin, 72.3% of patients would be eligible for minimally invasive treatment. This proportion decreases to 45.9% for an additional treatment margin of 5 mm. Shortest distances between tumors and critical organs are larger in older patients and in patients with less aggressive tumor subtypes. If a 10 mm safety margin to skin and pectoral muscle is required, more than two-thirds of patients would be eligible for minimally invasive breast cancer therapy.

Percutaneous image-guided cryoablation: current applications and results in the oncologic field

Percutaneous imaging-guided cryoablation (PICA) is a recently developed technique, which applies extreme hypothermia to destroy tumours under close imaging surveillance. It is minimally invasive, safe, repeatable, and does not interrupt or compromise other oncologic therapies. It presents several advantages over more established heat-based thermal ablation techniques (e.g. radiofrequency ablation; RFA) including intrinsic analgesic properties, superior monitoring capability on multi-modal imaging, ability to treat larger tumours, and preservation of tissue collagenous architecture. There has been a recent large increase in reports evaluating the utility of PICA in a wide range of patients and tumours, but systematic analysis of the literature is challenging due to the rapid pace of change and predominance of extensively heterogeneous level III studies. The precise onco-therapeutic role of PICA has not been established. This narrative review outlines the available evidence for PICA in a range of tumours. Current indications include curative therapy of small T1a renal tumours; curative/palliative therapy of small primary/secondary lung tumours where RFA is unsuitable; palliation of painful bone metastases; and urologic treatment of organ-confined prostate cancer. There is growing evidence to support its use for small hepatic tumours, and encouraging results have been obtained for breast tumours, extra-abdominal desmoid tumours, and management of higher-stage tumours and oligometastatic disease. However, the overall evidence base is weak, effectively restricting PICA to cases where standard therapy and RFA are unsuitable. As the technique and evidence continue to mature, the benefits of this emerging technique will hopefully become more widely available to cancer patients in the future.

First clinical experience with a dedicated MRI-guided high-intensity focused ultrasound system for breast cancer ablation

OBJECTIVES

To assess the safety and feasibility of MRI-guided high-intensity focused ultrasound (MR-HIFU) ablation in breast cancer patients using a dedicated breast platform.

METHODS

Patients with early-stage invasive breast cancer underwent partial tumour ablation prior to surgical resection. MR-HIFU ablation was performed using proton resonance frequency shift MR thermometry and an MR-HIFU system specifically designed for breast tumour ablation. The presence and extent of tumour necrosis was assessed by histopathological analysis of the surgical specimen. Pearson correlation coefficients were calculated to assess the relationship between sonication parameters, temperature increase and size of tumour necrosis at histopathology.

RESULTS

Ten female patients underwent MR-HIFU treatment. No skin redness or burns were observed in any of the patients. No correlation was found between the applied energy and the temperature increase. In six patients, tumour necrosis was observed with a maximum diameter of 3-11 mm. In these patients, the number of targeted locations was equal to the number of areas with tumour necrosis. A good correlation was found between the applied energy and the size of tumour necrosis at histopathology (Pearson = 0.76, p = 0.002).

CONCLUSIONS

Our results show that MR-HIFU ablation with the dedicated breast system is safe and results in histopathologically proven tumour necrosis.

KEY POINTS

• MR-HIFU ablation with the dedicated breast system is safe and feasible • In none of the patients was skin redness or burns observed • No correlation was found between the applied energy and the temperature increase • The correlation between applied energy and size of tumour necrosis was good.

Unresected Breast Cancer: Evolution of Imaging Findings Following Cryoablation

Cryoablation has been used to treat both benign and malignant breast tumors. In all but one published case, cryoablation in breast cancer has been followed by post-procedural tumor resection. We present a case of an 85-year-old woman with two nonpalpable breast cancers treated with cryoablation with 18 months of mammographic, ultrasound and histologic follow-up.

Percutaneous Image-Guided Cryoablation of Breast Cancer: A Systematic Review

A systematic review of the clinical safety and efficacy of percutaneous breast cancer cryoablation was performed. Of 202 papers screened, seven matched the inclusion criteria. Cryoablation was mainly performed under ultrasound guidance, and on average two cryoprobes were used. Complete local tumor control was noted in 73% of patients (mean follow-up, 8 mo). No major complications were noted. The cosmetic outcome was satisfactory. Breast cancer cryoablation is safe, although local tumor control is suboptimal. The best results are achieved with small (<15 mm) ductal tumors treated by application of multiple cryoprobes.

A Pilot Study of Ultrasound-Guided Cryoablation of Invasive Ductal Carcinomas up to 15 mm With MRI Follow-Up and Subsequent Surgical Resection

OBJECTIVE

The purpose of this study was to evaluate the effectiveness of ultrasound-guided cryoablation in treating small invasive ductal carcinoma and to assess the role of contrast-enhanced (CE) MRI in determining the outcome of cryoablation.

SUBJECTS AND METHODS

Twenty consecutive participants with invasive ductal carcinomas up to 15 mm, with limited or no ductal carcinoma in situ (DCIS), underwent ultrasound-guided cryoablation. Preablation mammography, ultrasound, and CE-MRI were performed to assess eligibility. Clinical status was evaluated at 1 day, 7-10 days, and 2 weeks after ablation. CE-MRI was performed 25-40 days after ablation, followed by surgical resection within 5 days.

RESULTS

Ultrasound-guided cryoablation was uniformly technically successful, and postablation clinical status was good to excellent in all participants. Cryoablation was not clinically successful in 15% (three of 20 patients). Three participants had residual cancer at the periphery of the cryoablation site. Two participants had viable nonmalignant tissue within the central zone of cryoablation-induced necrosis. Postablation CE-MRI had a sensitivity of 0% (0/3) and specificity of 88% (15/17). The predictive value of negative findings on CE-MRI was 83% (15/18). Correlations between cancer characteristics, cryoablation procedural variables, postablation CE-MRI findings, and surgical specimen features were not statistically significant. There were also no significant differences in participants with or without residual cancer.

CONCLUSION

In our pilot experience, ultrasound-guided cryoablation of invasive ductal carcinomas up to 15 mm has a clinical failure rate of 15% but is technically feasible and well tolerated by patients. The majority of cryoablation failures are manifest as DCIS outside the cryoablation field. Postablation CE-MRI does not reliably predict cryoablation outcome.

Cryoablation and Meriva have strong therapeutic effect on triple-negative breast cancer

Interleukin-6, a cytokine produced particularly by triple-negative breast cancers, strongly inhibits T cell responses in the tumor microenvironment. Here we tested cryoablation combined with Meriva (a lecithin delivery system of curcumin with improved bioavailability) in mice with metastatic breast cancer (4T1). Cryoablation involves killing of tumor cells through freezing and thawing, resulting in recruitment of tumor-specific T cells, while curcumin stimulates T cells through the reduction of IL-6 in the TME. Cryoablation plus Meriva accumulated and activated CD8⁺ T cells to multiple tumor-associated antigens such as Mage-b and Survivin (both expressed by 4T1 tumors). This correlated with a nearly complete reduction of 4T1 primary tumors and lung metastases while little effect was observed from saline or Meriva alone (28 d after tumor cell injection). The survival rate in the group of cryoablation plus Meriva was significantly improved compared to all control groups. Using a less aggressive 4T1 model expressing luciferase (4T1.2luc3), we demonstrated that all mice receiving saline or Meriva developed metastases in the lungs and a primary tumor (38 d after tumor cell injection; and died soon after that), but not the mice receiving cryoablation or cryoablation plus Meriva. However, on day 58 the mice receiving cryoablation developed 4T1.2luc3 metastases in the lungs, while mice receiving cryoablation plus Meriva were free of metastases. These results strongly suggest that cryoablation delayed the development of lung metastases on the short-term, but Meriva administered after cryoablation was significantly better in delaying the development of lung metastases and survival on the long-term.

Image-guided ablation in breast cancer treatment

In the past 2 decades, new and improved imaging technologies and the use of breast cancer screening have led to the detection of smaller and earlier-stage breast cancers. Furthermore, there has been a trend toward less aggressive treatment of small breast cancers, which has led to the development of less invasive alternatives than surgery with promising effectiveness, and less morbidity. Many patients are not satisfied with the cosmetic outcome after breast-conservation therapy. Better cosmesis can be achieved with less invasive techniques. Moreover, less aggressive treatment options would be very useful in patients older than 70 years with comorbidities that make surgery a difficult and sometimes life-threatening treatment. Minimally invasive ablation techniques have been studied in early-stage small tumors with the goal of attaining efficacy similar to that of breast-conservation therapy. These techniques would have less scarring and pain, lower costs, better preservation of breast tissue, superior cosmesis, and faster recovery time. Breast lesions can be destroyed by thermal methods, that is, by heating or freezing the tissue. There are 5 types of thermal ablations that have been or currently are in research clinical trials: cryoablation, radiofrequency, laser, microwave, and high-intensity focused ultrasound ablation. The first 4 methods destroy cancers using percutaneous image-guided probe placement. High-intensity focused ultrasound is noninvasive, performed without any skin opening.

Current status of imaging-guided percutaneous ablation of breast cancer

OBJECTIVE

The purpose of this article is to briefly describe the various techniques used for percutaneous ablation of breast cancer, their preliminary results, and their limitations. The techniques include thermotherapy (radiofrequency ablation, laser irradiation, microwave irradiation, and insonation with high-intensity focused ultrasound waves), cryotherapy, and irreversible electroporation.

CONCLUSION

The techniques used for percutaneous ablation of breast cancer raise many questions and issues that must be addressed before percutaneous ablation can be adopted for the treatment of early breast cancer.

Cryosurgery of breast cancer

With recent improvements in breast imaging, the ability to identify small breast tumors is markedly improved, prompting significant interest in the use of cryoablation without surgical excision to treat early-stage breast cancer. The cryoablation is often performed using ultrasound-guided tabletop argon-gas-based cryoablation system with a double freeze/thaw cycle. Recent studies have demonstrated that, as a primary therapy for small breast cancer, cryoablation is safe and effective with durable results, and can successfully destroy all cancers <1.0 cm and tumors between 1.0 and 1.5 cm without a significant ductal carcinoma-in-situ (DCIS) component. Presence of noncalcified DCIS is the cause of most cryoablation failures. At this time, cryoablation should be limited to patients with invasive ductal carcinoma <1.5 cm and with <25% DCIS in the core biopsy. For unresectable advanced breast cancer, cryoablation is a palliation modality and may be used as complementary for subsequent resection or other therapies.

Percutaneous image-guided ablation of breast tumors: an overview

Percutaneous non-surgical image-guided ablation is emerging as an adjunct or alternative to surgery in the management of benign and malignant breast tumors. This review covers the current state of the literature regarding percutaneous image-guided ablation modalities, clinical factors regarding patient selection, and future directions for research.

Cryosurgery in the treatment of women with breast cancer-a review

Cryoablation could be an alternative to surgical excision of breast cancer. The cytotoxic potential of cryosurgery has been shown in both animal models and studies conducted on humans. There are several advantages to be gained from ablation performed at very low temperatures and these include the method's simplicity, lack of pain, low morbidity, cost-effectiveness, and potential for positive cryo-immunologic effects. This manuscript reviews data concerning the use of cryoablation in the treatment of breast cancer.

US-guided percutaneous microwave coagulation of small breast cancers: a clinical study

PURPOSE

To determine the feasibility of percutaneous microwave coagulation (PMC) for the treatment of small solitary breast cancers.

MATERIALS AND METHODS

With approval of the institutional ethics committee and written informed consent, 41 patients with core-needle-biopsy-proved breast cancers 3.0 cm or less in diameter accessed by using ultrasonography (US) were recruited. US-guided PMC was performed with general anesthesia, followed immediately by mastectomy. Histochemical staining with α-nicotinamide adenine dinucleotide, reduced (NADH)-diaphorase was used to determine cell viability and the extent of PMC lesions.

RESULTS

The mean tumor volume was 5.26 cm(3) ± 3.80 (standard deviation), with a range from 0.09 to 14.14 cm(3). PMC was successfully performed in all cases, with complete tumor ablation as assessed by using US. The mean time to reach complete ablation was 4.48 minutes, ranging from 3 to 10 minutes. With microscopic examination, 37 of 41 cases (90%; 95% confidence interval [CI]: 76.9%, 97.3%) showed complete tumor coagulation, as observed by using α-NADH-diaphorase staining. Of 38 cases diagnosed with invasive ductal carcinoma, 36 cases (95%; 95% CI: 82.3%, 99.4%) showed complete tumor coagulation. Slight thermal injuries to the skin and pectoralis major muscle, which proved reversible, were found in three cases.

CONCLUSION

US-guided PMC of small solitary breast cancers is feasible. Nevertheless, larger-scale clinical trials are still needed to validate PMC for adoption into a standard clinical practice.

Ultrasound-guided core-needle biopsy of breast lesions

Objective

To review the role of ultrasound-guided core-needle biopsy (CNB) in the management of breast lesions.

Methods

Review of the most relevant literature on this topic.

Results

This technique shows a high sensitivity value of about 97.5% and it offers many advantages over other imaging techniques to guide a biopsy: non-ionising radiation, low cost, full control of the needle in real time, accessibility in difficult locations, multidirectional punctures and excellent comfort for patients and radiologists. All of these advantages have made this technique the most widespread used to perform a biopsy for a suspicious breast lesion. The most important limitation is the failure to perform a biopsy for lesions that are not seen on ultrasound. An adequate radiological–pathological correlation is necessary to minimise the false-negative results.

Conclusion

Ultrasound-guided CNB has proven to be a reliable technique for performing a biopsy for breast lesions that can be clearly seen on ultrasound.

Minimally-invasive thermal ablation of early-stage breast cancer: a systemic review

BACKGROUND

Minimally-invasive thermal ablation techniques provide an effective approach for local destruction of solid tumor. A novel application is the use for treatment of early-stage breast carcinoma.

METHODS

A broad search was conducted in Pubmed, Embase and the Cochrane databases between January 1990 and December 2009. Clinical results of the relevant articles were collected and analyzed.

RESULTS

The analyzed studies were almost all feasibility or pilot studies using different energy sources, patients, tumor characteristics and ablation settings. They were conducted in research settings for the assessment of technical safety and feasibility, and none of those was used alone in clinical practice. Despite many methodological differences, complete tumor ablation could be achieved in 76-100% of breast cancer patients treated with radiofrequency ablation, 13-76% in laser ablation, 0-8% in microwave ablation, 36-83% in cryoablation, and 20-100% in high-intensity focused ultrasound ablation.

CONCLUSION

Minimally-invasive thermal ablation is a promising new tool for local destruction of small carcinomas of the breast. Large randomized control studies are required to assess the long-term advantages of minimally-invasive thermal ablation techniques compared to the current breast conserving therapies.

Early-stage invasive breast cancers: potential role of optical tomography with US localization in assisting diagnosis

PURPOSE

To investigate the potential role of optical tomography in the near-infrared (NIR) spectrum with ultrasonographic (US) localization as a means of differentiating early-stage cancers from benign lesions of the breast.

MATERIALS AND METHODS

The protocol was approved by the institutional review boards and was HIPAA compliant; all participants signed an informed consent. One hundred seventy-eight consecutive women (mean age, 52 years; range, 21-89 years) who underwent US-guided biopsy were imaged with a hand-held probe consisting of a coregistered US transducer and an NIR imager. The lesion location provided by coregistered US was used to guide optical imaging. Light absorption was measured at two optical wavelengths. From this measurement, tumor angiogenesis was assessed on the basis of calculated total hemoglobin concentration (tHb) and was correlated with core biopsy results. For patients diagnosed with carcinomas and followed up with subsequent excision, the tHb was correlated with pathologic parameters.

RESULTS

There were two in situ carcinomas (Tis), 35 T1 carcinomas, 24 T2-T4 carcinomas, and 114 benign lesions. The mean maximum and mean average tHb of the Tis-T1 group were 102.0 micromol/L +/- 28.5 (standard deviation) and 71.9 micromol/L +/- 18.8, and those of the T2-T4 group were 100.3 micromol/L +/- 26.4 and 67.0 micromol/L +/- 18.3, respectively. The mean maximum and mean average tHb of the benign group were 55.1 micromol/L +/- 22.7 and 39.1 micromol/L +/- 14.9, respectively. Both mean maximum and mean average tHb levels were significantly higher in the malignant groups than they were in the benign group (P < .001). The sensitivity, specificity, positive predictive value, and negative predictive value for Tis-T1 cancers were 92%, 93%, 81%, and 97%. The corresponding values for T2-T4 tumors were 75%, 93%, 69%, and 95%.

CONCLUSION

The angiogenesis (tHb) contrast imaged by using the NIR technique with US holds promise as an adjunct to mammography and US for distinguishing early-stage invasive breast cancers from benign lesions.

Cryotherapy for breast cancer: a feasibility study without excision

PURPOSE

To assess the feasibility of percutaneous multiprobe breast cryoablation (BC) for diverse presentations of cancers that remained in situ after BC.

MATERIALS AND METHODS

After breast magnetic resonance (MR) imaging and thorough consultation, patients underwent BC after giving informed consent. This study was approved by the institutional review board. In 12 BC sessions, 22 breast cancer foci (stages I-IV) were treated in 11 patients who refused surgery by using multiple 2.4-mm cryoprobes. Five patients had recurrent disease and six had new diagnoses. With use of only local anesthesia, six patients were treated with ultrasonographic (US) guidance and five were treated with both computed tomographic (CT) and US guidance. Saline injections and warming bags were used to protect the skin. Procedure success was defined as 1 cm visible ice beyond all tumor margins. MR imaging and/or clinical follow-up were available for up to 72 months after BC.

RESULTS

US produced sufficient ice visualization for small tumors, whereas CT helped confirm overall ice extent. The mean pretreatment breast tumor diameter was 1.7 cm +/- 1.2 (range, 0.5-5.8 cm), and an average of 3.1 cryoprobes produced 100% procedural success with mean ice diameters of 5.1 cm +/- 2.2 (range, 2.0-10.0 cm). No significant complications, retraction, or scarring were noted. Biopsies at the margins of the cryoablation site immediately after BC and at follow-up were all negative. No local recurrences have been noted at an average imaging follow-up of 18 months.

CONCLUSIONS

In conjunction with thorough pre- and postablation MR imaging, CT/US-guided multiprobe BC safely achieved 1 cm visible ice beyond tumor margins with minimal discomfort, good cosmesis, and no short-term local tumor recurrences.

Lethal isotherms of cryoablation in a phantom study: effects of heat load, probe size, and number

PURPOSE

To assess the effects on the proportions of lethal ice (ie, colder than -30 degrees C) in phantoms with different heat loads created by varying the size and number of cryoprobes spaced 2 cm apart.

MATERIALS AND METHODS

Thermocouples at 0.5-, 1.0-, and 1.5-cm intervals from 1.7- or 2.4-mm-diameter cryoprobes were held by jigs accommodating a maximum of four cryoprobes. Agar phantoms (N = 24) used three sets of baseline temperatures: approximately 6 degrees C, 24 degrees C, and 39 degrees C. Temperatures during 15-minute freeze cycles were correlated with actual thermocouple locations seen within the ice by computed tomography (CT). Diameters and surface areas of the -30 degrees C lethal isotherm were assessed over time as percentages of the overall ice ball.

RESULTS

The high-heat load phantom experiments (39 degrees C) showed the greatest impact on lethal zones by percentage for all probe configurations. At 15 minutes, single-, double-, triple-, and quadruple-probe arrangements of 2.4-mm cryoprobes had average lethal ice diameters of 1.2, 3.3, 4.1, and 4.9 cm, respectively, comprising 13%, 46%, 51%, and 56% surface areas of lethal ice, respectively. Surface areas and diameters of lethal ice made by 1.7-mm cryoprobes were 71% and 84% of those made by 2.4-mm cryoprobes, respectively. Lethal ice resides less than 1 cm behind the leading edge for nearly all probe configurations and heat loads.

CONCLUSIONS

Single cryoprobes create very low percentages of lethal ice. Multiple cryoprobes overcome the high heat load of body temperature phantoms and help compensate for the lower freeze capacity of thinner cryoprobes.

MRI-guided interventions of the breast

MRI has proven to be a very reliable diagnostic tool in the detection and differential diagnosis of breast lesions. Some lesions are, even in retrospect, not detectable in x-ray or ultrasound images but MRI is able to detect lesions at a much smaller size than the average size of lesions depicted by x-ray and ultrasound. The aim in the future is to develop combined procedures where imaging, biopsy, and interventional therapies are combined in a single outpatient procedure. As a step toward this goal different interventional procedures are useful that include interstitial laser therapy (ILT), radiofrequency ablation (RFA), high-intensity focused ultrasound (HIFU), microwave ablation therapy, and cryotherapy. In this overview the main features and initial results of these procedures are described and discussed.

Accuracy of ultrasound-guided, large-core needle breast biopsy

Ultrasound-guided, large-core needle biopsy (US-LCNB) of suspicious breast lesions is acknowledged as less invasive and less expensive and less time consuming than surgical biopsy, and provides a histologic diagnosis with a comparable high degree. US-LCNB has been proven to help reduce the number of unnecessary surgeries for benign disease. Its limitations, however, are false-negative results and underestimation of disease. Thus, the demand for breast teams is to carefully adhere to the principles of triple assessment and imaging-histologic correlation, and follow-up of lesions with a specific benign histology after biopsy. Also, the acceptance of guidelines and rigorous quality controls help to reliably minimize the delay in the diagnosis of breast cancer in patients with false-negative biopsies. This paper aims to summarize the equipment and methods as well as the benefits and limitations of US-LCNB. Also, guidelines of quality assessment are suggested. Finally, recent developments which may help to overcome the limitations of US-LCNB will be discussed, i.e., directional vacuum-assisted biopsy (VAB), three-dimensional (3D) US-guided biopsy, as well as the use of tissue harmonic imaging (THI) and compound imaging (CI) during biopsy.